Zwitterionic liquid crystals as 1D and 3D lithium ion transport media

Abstract

Title: Zwitterionic liquid crystals as 1D and 3D lithium ion transport media Zwitterionic liquid crystals forming nanosegregated columnar and bicontinuous cubic phases are used as media for the transport of lithium ions within the well-defi ned ionic nanochannels. Enhanced conductivities are achieved for multicomponent systems including a zwitterionic liquid crystal, a lithium salt and propylene carbonate. We describe the development of self-assembled one-and three-dimensional lithium ion conductors composed of zwitterionic liquid crystals, lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) and propylene carbonate (PC). Two types of wedge-shaped zwitterions based on imidazolium dicyanoethenolate and sulfonate were synthesized. These compounds alone show liquid-crystalline (LC) columnar hexagonal (Col h ) phases and low ionic conductivities (10 À8 to 10 À7 S cm À1 ). The increase in the ionic conductivities was achieved by the addition of LiTFSI (10 À5 S cm À1 ) followed by that of PC (10 À4 S cm À1 ). Moreover, LC bicontinuous cubic (Cub bi ) phases are induced by tuning the ionic nature of the zwitterionic liquid crystal with the ratio of LiTFSI and PC. The dissociation of LiTFSI in the zwitterions and the ion-dipole interaction between the lithium ions and PC are shown to be significant keys for the enhancement of the conductivities and stabilization of the nanosegregated LC structures.

Functional Liquid Crystals towards the Next Generation of Materials

“…[114] Several ionic liquid crystals based on zwitterions have been designed and employed for proton-conductive materials. [115,116,[122][123][124][125][126][127] Fore xample,c ompound 12 exhibits ab icontinuous cubic phase in the co-existence of sulfonylimide derivatives 13 (Figure 4a). [127] In the bicontinuous cubic assembly,a3D continuous gyroid minimal surface is formed on which the sulfonic acid groups are arranged regularly.The fixing of the 3D molecular assembled structures has been achieved by modifying the ionic moiety to show glassification instead of crystallization.…”

Development of Nanostructured Water Treatment Membranes Based on Thermotropic Liquid Crystals: Molecular Design of Sub‐Nanoporous Materials

“…These compounds were expected to exhibit thermotropic Col h or Cub bi phases with 1D or 3D uniform sub-nanopores in the membranes. [44][45][46][47][48] We previously reported on water treatment with self-organized sub-nanoporous membranes prepared by photopolymerization of the triethylammonium molecule 1(12) in the Cub bi phase (Figure 1). [19] The Cub bi membrane showed selective permeation for the sulfate ion in addition to a NaCl rejection rate and water permeability that were comparable to those of commercial NF membranes.…”

Dicyanamide Salts that Adopt Smectic, Columnar, or Bicontinuous Cubic Liquid‐Crystalline Mesophases

“…Bulky [NTf 2 ] À anions( which are conformationally flexible but can also adopt ab ents hape) have already been incorporated into bicontinuousc ubic mesophases formed by low-molar-mass ionic and zwitterionic LCs but, in those cases, the anionsw ere located primarily on an IPMS on which the steric restrictions are less severe than inside the polar channels of an inverted-type Cub V phase. [84][85][86][87][88][89][90] We also note that thiocyanate salt 9 exhibits only aC ol hex phase. Samples of compound 9 wereheated and cooled at different rates (down to 1 8Cmin À1 ), but, in all cases, evidencef or ac ubic phase was not observed by POM or XRD.…”